Author Topic: SWORDS nanosat launch vehicle  (Read 40903 times)

Offline Jim

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Re: SWORDS nanosat launch vehicle
« Reply #20 on: 08/26/2013 01:54 PM »

True but it would eliminate running out of propellant as a life ending failure mode. CMGs worked pretty well on Skylab and are working quite well on ISS.


Not really.  Skylab had GN2 thrusters for desaturation and the ISS has Progress tankers bringing up prop for the SM thrusters and the Progress themselves are used for desaturation.

Skylab would have run out of GN2 if it weren't for some unusual weather conditions that allowed NASA to load 25% more than planned.  Skylab ended up using 50% of the load before the first crew visit.

Magnetic torque bars and a low earth orbit is the only way to get out of using thrusters with CMG's.  Kepler has thrusters.
« Last Edit: 08/26/2013 01:58 PM by Jim »

Offline dchill

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Re: SWORDS nanosat launch vehicle
« Reply #21 on: 08/26/2013 02:17 PM »
...
Magnetic torque bars and a low earth orbit is the only way to get out of using thrusters with CMG's.  Kepler has thrusters.

I suppose using gravity gradient would be a stretch.  (Pun intended)

Offline kevin-rf

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Re: SWORDS nanosat launch vehicle
« Reply #22 on: 08/26/2013 06:45 PM »
For LEO, I have always wondered if control surfaces (paddles and rudders) could be used.

I suspect, like gravity gradient stabilization, the effect is so weak that once the CMG's get saturated you would have to wait weeks if not moths to de-saturate them. 
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Online john smith 19

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Re: SWORDS nanosat launch vehicle
« Reply #23 on: 08/26/2013 06:55 PM »
Magnetic torque bars and a low earth orbit is the only way to get out of using thrusters with CMG's.  Kepler has thrusters.

Agreed. But TBH LEO is where I would expect most of these payloads to be placed. Above that level you have the GPS constellation and (IIRC) the Iridium constellation before you get to GEO.

AFAIK nothing in the major existing constellations is small enough to be launched on this, unless someone is planning to re-configure those functions as some kind of "swarm" concept that can be launched in small sections.

Outside of LEO I would expect thrusters would be needed to dump momentum. One benefit of this payload size might be people will implement a one sensor, one payload approach. But without launching near the theater of operations there will be likely be a payload hit [edit from 28degs.
 
Given the mass limits an emphasis on passive devices like gravity gradient stabilization and body mounted solar cells seems quite a good idea.]
« Last Edit: 08/26/2013 09:17 PM by john smith 19 »
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Offline kevin-rf

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Re: SWORDS nanosat launch vehicle
« Reply #24 on: 08/27/2013 12:09 PM »
Honestly, when providing communications in regional conflicts, short of GTO, a highly eccentric orbit makes sense. It can be tailored to a geographic region and provides the most dwell time over the battle space.

Look up Blue Scout and Emergency Rocket Communications System (ERCS).
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Online john smith 19

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Re: SWORDS nanosat launch vehicle
« Reply #25 on: 09/21/2013 10:15 AM »
Honestly, when providing communications in regional conflicts, short of GTO, a highly eccentric orbit makes sense. It can be tailored to a geographic region and provides the most dwell time over the battle space.
True.

I'm also guessing that as the satellite is spending less time in the (relatively) more dense lower atmosphere it's lifetime would also be improved.

My instinct remains for a payload this size you should avoid thrusters and use CMGs, magnotorquers and passive mechanisms like gravity gradient to control attitude

However with no thruster you now need the LV to ensure it's in the right orbital plane.
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Offline KSC Sage

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Re: SWORDS nanosat launch vehicle
« Reply #26 on: 03/17/2014 11:51 AM »
SWORDS has been cancelled.  It was cancelled last Thursday, 13 March 2014.  The KTE horizontal engine testing will run through completion and then the program will be totally closed up by September this year.

Offline Jim

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Re: SWORDS nanosat launch vehicle
« Reply #27 on: 03/17/2014 01:39 PM »
SWORDS has been cancelled.  It was cancelled last Thursday, 13 March 2014.  The KTE horizontal engine testing will run through completion and then the program will be totally closed up by September this year.

That is a good thing.  Never should have got as far as it did.

Offline jongoff

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Re: SWORDS nanosat launch vehicle
« Reply #28 on: 03/18/2014 01:23 AM »
SWORDS has been cancelled.  It was cancelled last Thursday, 13 March 2014.  The KTE horizontal engine testing will run through completion and then the program will be totally closed up by September this year.

That is a good thing.  Never should have got as far as it did.

Good thing they cancelled the NanoSat Launch Centennial Challenge, due to SWORDS being such a sure thing...

Can't say I'm totally surprised though. They've been getting paid for "working on" SWORDS and its predecessors under various contracts (and various names) for nearly a decade now, and I don't think I've seen anything to show for it.

~Jon

Offline edkyle99

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Re: SWORDS nanosat launch vehicle
« Reply #29 on: 03/18/2014 02:41 AM »
SWORDS has been cancelled.  It was cancelled last Thursday, 13 March 2014.  The KTE horizontal engine testing will run through completion and then the program will be totally closed up by September this year.
Has a reason been given for the cancellation?

 - Ed Kyle

Offline Danderman

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Re: SWORDS nanosat launch vehicle
« Reply #30 on: 03/18/2014 03:00 AM »
With "free" Minotaurs available, why would DoD invest in a new launcher?

Offline Jim

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Re: SWORDS nanosat launch vehicle
« Reply #31 on: 03/18/2014 12:25 PM »
With "free" Minotaurs available, why would DoD invest in a new launcher?


Because the DOD is not monolithic and SWORDS was an Army project.  Also, Minotaurs are not transportable.

Offline jongoff

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Re: SWORDS nanosat launch vehicle
« Reply #32 on: 03/18/2014 04:35 PM »
With "free" Minotaurs available, why would DoD invest in a new launcher?


Because the DOD is not monolithic and SWORDS was an Army project.  Also, Minotaurs are not transportable.

SWORDS was also focused on much smaller payloads than a Minotaur launches. About 10x smaller payloads. Not that SWORDS was the right solution, but there are a lot of people interested in having dedicated nanosat or smallsat launch vehicles (ie in the sub 100kg to LEO range).

~Jon

Offline edkyle99

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Re: SWORDS nanosat launch vehicle
« Reply #33 on: 03/19/2014 02:16 PM »
Here's a statement by Lt. Gen. David L. Mann, Commanding General, U.S. Army Space and Missile Defense Command and Army Forces Strategic Command that was made on March 12, 2014 before the Committee on Armed Services Strategic Forces Subcommittee of the U.S. Senate.  Lt. Gen. Mann describes SWORDS as an ongoing project that has NASA support.
http://www.armed-services.senate.gov/imo/media/doc/Mann_03-12-14.pdf

Here, also, is a presentation on SWORDS from mid-2013 that provides more details than I've seen elsewhere.
http://smdsymposium.org/wp-content/uploads/2013/09/Rich-White-presentation.pdf

 - Ed Kyle
« Last Edit: 03/19/2014 02:47 PM by edkyle99 »

Offline HMXHMX

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Re: SWORDS nanosat launch vehicle
« Reply #34 on: 03/19/2014 11:39 PM »
SWORDS has been cancelled.  It was cancelled last Thursday, 13 March 2014.  The KTE horizontal engine testing will run through completion and then the program will be totally closed up by September this year.
Has a reason been given for the cancellation?

 - Ed Kyle

One reason given was the cost of tanks was coming in at 10x what they could afford.

Offline jongoff

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Re: SWORDS nanosat launch vehicle
« Reply #35 on: 04/29/2014 02:08 AM »
SWORDS has been cancelled.  It was cancelled last Thursday, 13 March 2014.  The KTE horizontal engine testing will run through completion and then the program will be totally closed up by September this year.
Has a reason been given for the cancellation?

 - Ed Kyle

One reason given was the cost of tanks was coming in at 10x what they could afford.

That's amusingly ironic, since the "low cost tanks" were a key part of why they selected such a weird design concept...

~Jon

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